The present invention relates generally to the field of safety devices. More particularly, the present invention is directed to a lockout device for preventing someone from operating a manually operated valve.
A system for transporting fluids, such as gases or liquids, or for providing a vacuum typically incorporate various types and quantities of valves and other components to measure and control the fluid as it passes through the system to its point of utilization. Often it is necessary to isolate and shut down one or more portions of the system to perform modifications and/or routine maintenance on the system while the remaining portion of the system remains energized. Often this is accomplished by closing one or more isolation valves that isolates the shut-down, or de-energized, portion(s) of the system from the energized portion.
To protect workers from harm due to contact with, e.g., hazardous materials, high pressures, high temperatures and the like contained within still-energized portion of the system, it is often desirable to lock each isolation valve in its closed position to prevent someone from opening the valve while work is being performed on the system. In fact, government regulations, e.g., regulations promulgated by the Occupational and Safety Hazards Administration (OSHA), often require under penalty of law that valves be locked during maintenance and modification outages.
The semiconductor manufacturing and chemical manufacturing industries are two examples of many industries that utilize often vast and complex piping systems. These systems typically contain manually-operated isolation valves that must be locked into their closed positions during maintenance and modification outages. Such manually-operated valves are many and diverse, requiring different types of lockout devices to lock the corresponding valves in their closed positions.
For example, some isolation valves are known as xe2x80x9cquarter-turnxe2x80x9d valves, meaning that the handles of these valve are rotatable 90xc2x0 between their fully-open positions and their fully-closed positions. Many of these valves have single-member lever-type handles, wherein the handle of each valve is parallel to the valve""s inlet and outlet pipes when the valve is installed in a straight run of pipe. Correspondingly, the handle of the valve is positioned perpendicular to the inlet and outlet pipes when the valve is in its closed position.
A conventional lockout device for this lever-type isolation valve typically includes a tubular member that generally fits over the valve stem and body of the valve and has a longitudinal open-ended slot for receiving the valve handle as the device is installed over the valve and holding the handle in its fully closed position, i.e., perpendicular to the inlet and outlet pipes. The device generally straddles the valve and includes a pair of notches at its lower end that, when properly seated on the valve, each correspondingly engage one of the inlet and outlet pipes to prevent the device and handle from being rotated relative to the valve body. An example of such a lockout device is disclosed in U.S. Pat. No. 812,021 to Dahl. A drawback of this device is that the open-ended slot extends substantially entirely along the height of the device and is open at its lower end so that the torsional rigidity of the device along its longitudinal axis is significantly diminished. Depending upon the material selected for making the lockout device and the wall thickness of the device, the torsional rigidity may be so small that the device may be easily torsionally distorted, and the valve handle turned, by application of a relatively small force.
In addition to a lever-type handle, some valves have cross-shaped handles having raised indicia disposed along one of two mutually orthogonal axes that define the cross shape. Until the present invention, it appears there have been no lockout devices that utilize such raised indicia in a manner that the raised indicia prevent a lockout device from being properly seated on a valve unless the handle is in its fully closed position.
Another shortcoming of conventional lockout devices is that most are secured to a valve only when it is desired to lock the valve. When these lockout devices are not being used, they must be stored, typically in a location remote from the valves. At least one valve guard, as disclosed in U.S. Pat. No. 3,980,099 to Youngblood, may be permanently mounted to the piping adjacent the corresponding valve. However, when the guard is not being used, its locking member is pivoted away from the valve handle such that it projects radially outward from the piping a significant distance beyond the valve handle. The Youngblood valve guard, therefore, requires a significant amount of space to be operated. In some piping systems, such space may not be available.
The various embodiments of the lockout device of the present invention overcome these and other shortcomings of conventional lockout devices.
In a first aspect, the present invention is directed to a lockout device for a valve having a valve body and a handle. The lockout device comprises a member defining a space for receiving at least a portion of the valve body and at least a portion of the handle. The member has a longitudinal axis and a height extending along the longitudinal axis, a lower end and a first opening at the lower end. A second opening is provided in the member for receiving at least a portion of the handle. The second opening is spaced from the lower end of the member such that a portion of the member is present between the second opening and the lower end of the member.
In second aspect, the present invention is directed to a lockout device for a valve that includes a body and a handle having a surface and raised indicia located on, and extending away from, the surface. The lockout device comprises a member having a sidewall an end wall. The sidewall and the end wall define a space for receiving at least a portion of the handle and at least a portion of the body. Lockout device is provided with means for receiving the raised indicia, and not the handle, only when the handle is oriented properly with respect to the lockout device when the device is engaged with the valve. The means is located on the member.
In a third aspect, the present invention is directed to a lockout device for a valve having a valve body and a handle. The lockout device comprises a base having a longitudinal axis and adapted for engaging at least a portion of the valve body. A locking member is slidably engaged with the base and has a retracted position relative to the base, an extended position relative to the base and at least one slot for engaging the handle of the valve when the locking member is in its extended position. The locking member is slidable between the retracted position and the extended position along the longitudinal axis.